A light emitted diode (LED) refers to a device which converts an electric signal to infrared rays or light using properties of a compound semiconductor, and is advantageous in terms of having a long life span compared to conventional other light sources and causing little environmental pollution because it does not use harmful substance unlike a fluorescent light or the like in which mercury or the like is used. In addition, an LED is advantageous in that visibility is excellent due to a high color temperature and power consumption is low when compared to other light sources.
Thanks to the advancement and supply of LED technology, a trend of a lighting apparatus is advancing from using conventional light sources such as a fluorescent light or the like to using an LED light source. For example, as disclosed in Korean Patent Laid-Open Publication No. 10-2012-0009209, a lighting apparatus which performs a surface light-emitting function using an LED light source and a light guide plate has been proposed.
In addition, in some conventional technologies, a lighting apparatus in which surface light-emitting performance is enhanced by adding an optical sheet such as a diffusion sheet, a prism sheet, a protective sheet, or the like to the light guide plate has been suggested.
However, a conventional lighting apparatus using an LED light source is limited in thinning a thickness of an entire product due to a thickness of the light guide plate itself, is disadvantageous due to being difficult to apply to a housing or an application in which a curve is formed because a material of the light guide plate is not flexible, and is disadvantageous in designing a product and modifying a design due to the light guide plate. Accordingly, a solution which can be easily applied to diverse applications such as indoor and outdoor lighting, vehicle lighting, or the like, and can effectively implement light images as desired is required.